Hyperbaric dressing

ABSTRACT

A hyperbaric dressing has a fluid impermeable sheet and a fluid permeable layer with a sheet of porous material positioned between these two layers with passageways to permit fluid to flow out of the dressing.

This invention relates to a hyperbaric dressing for use in the treatmentof wounds, more particularly, a hyperbaric dressing for supplying oxygento a wound and for allowing or causing exudate to be removed from thewound.

It is known that a supply of oxygen to a wound or through the skincovering a wound promotes healing and reduces scarring of damagedtissue. Typically, oxygen is absorbed by tissue fluids, thus improvingthe oxygen content of intercellular fluids and/or promoting metabolismand repair of the damaged tissue. As such, there are numerous ailmentswhich may benefit from the topical application of oxygen to damagedtissue, for example, osteomylelitis, tendon, ligament and cartilagedamage, fractures, burns, scalds, necrotising fasciitis, such aspyoderma gangrenosum, pressure-induced decubitus (bed sores), venous anddiabetic foot and leg ulcers, as well as cuts, abrasions and surgicallyinduced wounds and incisions.

At present, there are several methods for supplying a wound with oxygen.One such method is to place the entire affected limb within a sealedcontainer which controls oxygen pressure within the container. However,these containers are expensive, difficult to sterilise and may limit apatient's mobility. Furthermore, as a whole limb is placed within thecontainer, large areas of normal tissue are subjected to highconcentrations of oxygen. Thus, there is a need for a remedy for locallysupplying a wound with oxygen without the associated disadvantages ofprior art methods discussed above.

Accordingly, one aspect of the invention resides in a hyperbaricdressing comprising first and second layers and delivery means arrangedto supply a fluid, such as a gas, to the first layer, wherein the firstlayer is associated with the second layer to allow the fluid to flow inone direction through the second layer and to allow another fluid, suchas a liquid, to flow in the opposite direction through the second andfirst layers.

The hyperbaric dressing may further comprise a self-adhesive layer,preferably adjacent the second layer, with a peel-off backing layer toenable the dressing to be affixed to a surface, such as a patient's skinsurrounding a wound. The adhesive of any such self-adhesive layer mayextend over the whole area of that layer or partially thereover. In thelatter case, the adhesive may be in strip form extending around thesecond layer between the peripheral edges of the first and secondlayers.

When the first fluid is a gas, the other fluid may be a liquid orvice-versa.

The first and/or second layer may be a gas-permeable layer.

The first and second layers may be secured together by means of sonicwelding or induction heating, for example. Typically, this involvessealing the peripheral edges of the layers together to form, say, apouch and, possibly, sealing together in-register portions of the firstand second layers. Any gas-impermeable first layer may be formed, forexample by vacuum, into recesses such as circular recesses, whose basesmay be secured to in-register portions of the second layer, withpassageways extending through the remainder of the first layer betweenany such recesses for the transmission of, say, oxygen or other fluidthrough the passageways.

The first and second layers are typically made of suitable plasticsmaterials and, preferably, the first layer is made of polyurethane.

The layers are typically in the range of 0.05 mm to 1 mm thick and mostpreferably in the range of 0.1 mm to 0.5 mm thick.

Additionally, where adjacent portions of the two layers are sealedtogether, or otherwise associated with each other, holes or otherperforations through both layers and, optionally, any self-adhesivelayer can be made. These holes can be made by any appropriate method,such as, laser drilling. The diameters of the holes should be such thatliquids, such as exudate from a wound, may pass through them, and,hence, through the second and first layers, with comparative ease.

Alternatively, the first layer may comprise a sheet of porous material,such as an open cell foam material, which is permeable to a fluid, suchas a gas, and which is adjacent the second layer, with a fluidimpermeable sheet applied to the outer surface of the porous sheetremote from the second layer.

The porous sheet is preferably provided with means for communicationwith a source of gas, for example, an oxygen generator.

In a preferred embodiment to be described in more detail hereinbelow,the porous sheet is provided with an array of apertures through whichthe fluid impermeable outer sheet and second layer can be sealedtogether, with further holes provided therein for allowing or causing afluid, such as exudate from a wound to which the dressing is applied, toflow through the second and first layers in a direction opposite to thatof the flow of gas, such as air or oxygen, through the second layer andon to the associated wound.

The further holes may be formed by any suitable means during manufactureof the dressing, for example, by laser drilling through thesealed-together fluid impermeable sheet of the first layer and thesecond layer.

In this manner, and when the dressing is in use and applied to a wound,oxygen can be caused to flow through the porous sheet of the first layerand through the gas permeable second layer to the wound, whilst anyexudate from the wound can flow in the reverse direction to the oxygenthrough the second and first layers via the further holes, as discussedabove.

The fluid-delivery means may be arranged to supply to the dressing anysuitable gas, for example air, although the most preferred gas isoxygen.

Typically, the fluid-delivery means is a tube. One end of the tube maybe attached, either releasably or permanently, for example sealed, tothe dressing, with the other end being capable of being connected, viaappropriate means, to a gas cylinder, compressor or other supply of gas.Preferably, that other tube end is attachable to are oxygen cylinder orgas generator which is preferably portable.

In an embodiment to be described hereinbelow, the fluid-delivery means,which is essentially a gas-delivery means, is integral with the twolayers of the dressing, with portions thereof forming a tube forattachment to, say, an oxygen source. In this case, two spaced sealinglines can form the integral tube between the two layer portions of thedressing.

It will, of course, be appreciated that many different sizes of dressingcould be required, depending upon the size of the wounds to be dressed.Thus, dressings may be formed into any appropriate shape and be of anysuitable size. Alternatively, the dressings may be cut to size.

Furthermore, more than one gas-delivery device may be utilised to helpstandardise the amount of oxygen passing through the dressing throughoutthe whole wound-covering area of the dressing.

In use, this dressing can be applied to a wound by way of removing anypeel-off layer to expose any self-adhesive layer and then placing thedressing directly over the wound, the exposed self-adhesive layer(s)preferably being placed upon unaffected skin around the wound.

A standard absorbent or compression bandage can then be placed over thedressing to soak up any exudate which seeps from the wound. Oxygen issupplied to the dressing via the gas-delivery means and, in turn,pressurises the dressing forcing the oxygen into contact with the wound.

Additionally or alternatively, exudate may be removed by other suitablemeans, for example, a vacuum source connected to the exterior of thedressing.

A second aspect of the invention resides in a hyperbaric dressingcomprising first and second layers and delivery means arranged to supplya fluid, such as a gas, to between the two layers, wherein the deliverymeans is integral with the first and second layers, preferably beingformed as a tube from portions of those two layers.

The invention also provides, in combination, a hyperbaric dressing asdefined above in accordance with the first or second aspect thereof orany modification described above and an absorbent or compression outerbandage or dressing. Each outer bandage or dressing may substantiallyseal any un-sealed or cut edges of a hyperbaric dressing, so as to allowhyperbaric fluid pressure to be maintained.

Further, the invention can provide, in combination, a hyperbaricdressing as defined above in accordance with the first or second aspectof the invention, or any modification thereof, and a portable oxygengenerator connected or connectable to the fluid delivery means.

In a third aspect, the invention provides a method of cosmeticallytreating a human being or animal to reduce the existence and/orvisibility of scar tissue following surgery or illness, comprising thesteps of:

-   -   placing a hyperbaric dressing, in accordance with the first or        second aspect of the invention defined above or any modification        thereof, on to a wound; and    -   supplying the so-applied dressing, and thus the wound, with        oxygen, preferably from a portable oxygen generator.

Additional to the above-mentioned method may be the step of applying astandard absorbent or compression bandage over the dressing so as toabsorb or otherwise collect any exudate which may seep from the woundthrough the dressing. Additionally or alternatively, exudate may beremoved from the dressing under vacuum.

In order that the present invention may be more fully understood,embodiments of hyperbaric dressings will now be described by way ofexample and with reference to the accompanying drawings in which:

FIG. 1 is a section, in elevation, of a first upper layer of a firstembodiment of hyperbaric dressing;

FIG. 2 is a section, in elevation, of the first upper layer of thehyperbaric dressing, as shown in FIG. 1, secured to a second lower layerof the partially-formed dressing;

FIG. 3 is a section, again in elevation, of the upper and lower layersof the partially-formed dressing, as shown in FIG. 2, with aself-adhesive layer attached removably to the lower layer;

FIG. 4 is a section, again in elevation, of the hyperbaric dressing inits final form;

FIG. 5 is a plan view of the dressing shown in FIG. 4;

FIG. 6 is a sectional diagrammatic view of the dressing shown in FIGS. 4and 5 in use;

FIG. 7 is a plan view of a second embodiment of hyperbaric dressing;

FIG. 8 is a section, in elevation, of the dressing shown in FIG. 7 butin a partially assembled condition prior to full manufacture;

FIG. 9 is a section, again in elevation, of the dressing shown in FIG.7;

FIG. 10 is a plan view of a third embodiment of hyperbaric dressing; and

FIG. 11 is a partial sectional view of the dressing shown in FIG. 10.

Referring firstly to FIGS. 1 to 5 of the accompanying drawings, a firstembodiment of hyperbaric dressing, indicated generally at 1 in FIGS. 4and 5, comprises a first, upper layer 2 which is formed as follows.

A partially-formed first, upper layer, indicated generally at 2′ inFIGS. 1 to 3, comprises a flexible, polyurethane film 3 which is 0.01 mmto 0.05 mm thick, is hydrophilic and is gas, namely oxygen, impermeable.The film 3 has circular recesses 4 vacuum formed therein, with the bases5 of the recesses 4 bonded at 6 to a partially-formed second, lowerlayer 7′ which is gas, namely oxygen, permeable and hydrophobic. In thismanner, passageways 8 for the transmission of oxygen therethrough, areprovided between the gas impermeable, hydrophilic first, upper layer 2′and gas permeable, hydrophobic second, lower layer 7′, such passagewaysbeing in communication with a tube 9 connected to a source of oxygen(not shown).

As shown in FIG. 3, a partially-formed, peel-off layer 10′ andself-adhesive layer 12′ are provided on the underside of the lower layer7′.

To form the final hyperbaric dressing, as shown generally at 1 in FIGS.4 to 6, holes 11 are punched, or otherwise formed, through the bases 5of the circular recesses 4, the lower layer 7′ and the peel-off andself-adhesive layer 10′, 11′. Thus, the final dressing 1, as shown inFIGS. 4 to 6, comprises perforated first, upper, second, lower andself-adhesive, peel-off layers 2, 7, 10, 12.

The so-formed dressing 1 is pouch-like in nature, with the peripheriesof the layers 2, 7 sealed together.

FIG. 6 shows the hyperbaric dressing 1 in use, wherein the peel-offlayer 10 has been removed from the self-adhesive layer 11 and thedressing 1 has been positioned on a patient's skin covering a wound 20.

Oxygen at a pressure greater than atmospheric pressure is fed from aportable oxygen generator (not shown) through the tube 9 into thepassageways 8 of the dressing 1 which, as a compresse, becomes partiallyinflated. The oxygen pressure inside the dressing 1 forces some oxygenthrough the second, lower gas-permeable layer 7, as indicated by O₂ andthe one direction arrows A in FIG. 6, and on to the wound 21. Anyexudate from the wound 20, as indicated by E, in FIG. 6, migrates fromthe wound 20 through the holes 11 in the other direction of arrows B tothe side of the dressing 1 remote from the wound 20. At this point theexudate E can be absorbed by an outer absorbent bandage (not shown) orremoved under vacuum.

Rather than using a portable oxygen generator, oxygen may be provided atthe necessary pressure against atmospheric pressure by any othersuitable means, for example, an oxygen cylinder or oxygen generator,connected to the remote end of the tube 9.

Referring now to FIGS. 7 to 9 of the drawings, a second embodiment ofhyperbaric dressing, indicated generally at 21 in FIGS. 7 and 9,comprises a first, upper layer 22 including a gas impermeable sheet 23of polyethylene film and a thicker sheet 33 of an open cell foammaterial which is at least gas-permeable and which has a substantiallyregular array of circular apertures 24 extending through the thicknessthereof.

In FIG. 8, there is shown a partially-formed first, upper layer 22 ¹comprising the sheet 23 ¹ of gas-impermeable, polyethylene film and theintermediate sheet 33 ¹ of open cell foam material, with the circularapertures shown at 24 ¹. A second, lower layer 27 ¹ is provided by agas-permeable sheet of a material sold under the Trade Mark “CAPLA”.

To form the final hyperbaric dressing, as shown generally at 21 in FIGS.7 and 9, the outer sheet 23 ¹ of the first layer 22 ¹ and the second,lower layer 27 ¹ are, using a suitable tool (not shown), heat sealedtogether through the circular apertures 24 ¹. Simultaneously orsubsequent to such heat sealing, circular holes 31 are formed throughthe resulting heat sealed-together sheet 23 of the first layer 22 andthe second, lower layer 27 within the apertures 24, as shown inparticular in FIG. 9.

As in the case of the first embodiment of hyperbaric dressing 1discussed above with reference to FIGS. 4 to 6, peel-off andself-adhesive layers (also not shown) may be employed.

In use of the hyperbaric dressing 21, it is applied over a wound andoxygen at a pressure greater than atmospheric pressure is fed from, say,a portable oxygen generator (not shown) through a tube received in acut-out socket 40 provided in one edge of the open cell foam sheet 33 ofthe first layer 22. Because the gas impermeable sheet 23 is sealed tothe open cell foam sheet 33 of the first layer 22, the oxygen pressureinside the open cell foam sheet 33 forces oxygen through the second,lower gas-permeable layer 27 in one direction and on to the wound.

Because also the second, lower gas-permeable layer 7 is impermeable toliquid, any exudate from the wound migrates therefrom through the holes31 in the circular apertures 24 in the other direction toward the sideof the dressing 21 remote from the wound. At this point, the exudate canbe absorbed by an outer absorbent bandage (not shown) or removed undervacuum or by any other suitable means.

As in the case of the first embodiment of hyperbaric dressing 1described above, rather than using a portable oxygen generator, oxygenmay be provided at the necessary pressure against atmospheric pressureby any other suitable means, for example, from an oxygen cylinderconnected to the tube inserted in the socket 40.

Turning now to a third embodiment of hyperbaric dressing, as indicatedgenerally at 41 in FIGS. 10 and 11, a first upper layer 42 comprises agas impermeable sheet 43 of polyethylene film and a thicker sheet 53 ofan open cell foam material which is gas-permeable and which has asubstantially regular array of circular apertures 44 extending throughthe thickness thereof.

A second, lower layer 47 is provided by a gas-permeable sheet ofmaterial sold under the Trade Mark “CAPLA”.

This arrangement is very similar to the second embodiment describedabove with reference to FIGS. 7 to 9, as are the circular holes 51extending through both the upper and lower layers 42,47 within thebounds of the apertures 44 of the foam sheet 53.

However, in this third embodiment of dressing, the gas deliveryarrangement is provided by an integral tube 60 formed from adjacentportions of the sheet 43 of the first, upper layer 42 and the lowerlayer 47, as shown in detail in FIG. 11.

Formation of the integral tube 60 is carried out by providing a pair ofspaced, sealing weld lines, as shown at 61, between the gas-impermeablesheet 43 of the upper layer 42 and the gas-permeable lower layer 47, thesheet 43 and the layer 47 already having been sealed together at 55 overthe major portions of their confronting surfaces. The integral tube 60is thus formed between respective portions 43 ¹ and 47 ¹ of the sheet 43and layer 47 which are not sealed together. In use, the end 62 of thetube 60 remote from the dressing 41 can be connected to an oxygen source(not shown) by means of a connector 63.

The spaced sealing weld lines 61 can be formed within the material 64before it is cut-away or otherwise removed from the dressing 41 duringmanufacture thereof, such material 64 being constituted by the sheet 43of the upper layer 42 and the lower layer 47.

It has been found that this integral tube 60 provides a very usefulmeans for supplying oxygen to the interior of the dressing 42 and, also,that only about 2% of oxygen from the oxygen source is lost through thatpart of the tube 60 constituted by the portion 47 ¹ of the lower layer47.

Thus, the invention provides a hyperbaric dressing which accomplishesthe same function as the known oxygen chambers, bags and the likediscussed above but at much less expense. Also, it is more easilypositioned upon a patient and is easily removable after use. Further, itis readily disposable and requires no sterilisation after use. Duringuse, a patient can enjoy substantially full mobility, particularly if asmall portable oxygen generator or cylinder is available, whilstemploying any suitable existing type of absorbent dressing over thehyperbaric dressing for absorbing exudate E through the holes.

The invention claimed is:
 1. A hyperbaric dressing comprising; a firstlayer and a second layer associated together to form a) an oxygen supplyportion comprising a pouch in which the first layer is a sheet formed ofa fluid-impermeable material and the second layer is a sheet formed of agas-permeable and liquid-impermeable material; and b) an exudate removalportion comprising at least one sealed-together in-register portion ofthe first and second layers, defining a hole through the first andsecond layers; and a delivery means arranged to supply oxygen to betweenthe first and second layers to pressurize the pouch; wherein the oxygencan permeate out of the pouch through the second layer, wherein a fluidcomprising wound exudate cannot permeate through the second layer intothe pouch, and wherein the hole defined through the first and secondlayers of the at least one sealed-together in-register portion is ofsuch a diameter to allow the fluid comprising wound exudate to flowthrough the second and first layers.
 2. A dressing according to claim 1,further comprising a self-adhesive layer.
 3. A dressing according toclaim 2, wherein the self-adhesive layer is adjacent the second layer.4. A dressing according to claim 1, wherein the fluid-impermeable sheetof the pouch is gas-impermeable.
 5. A dressing according to claim 1,wherein the peripheral edges of the first and second layers are securedtogether to form the pouch.
 6. A dressing according to claim 1, whereinthe first layer includes recesses, wherein bases of the recesses aresecured to in-register portions of the second layer.
 7. A dressingaccording to claim 1, wherein the fluid-impermeable sheet and thegas-permeable and liquid-impermeable sheet are made of a plasticsmaterial.
 8. A dressing according to claim 7, wherein thefluid-impermeable sheet is made of polyurethane.
 9. A dressing accordingto claim 1, wherein the fluid-impermeable sheet and the gas-permeableand liquid-impermeable sheet are in the range of 0.05 mm to 1.00 mmthick or are in the range of 0.1 mm to 0.5 mm thick.
 10. A dressingaccording to claim 1, wherein said delivery means comprises anintegrally-formed tube.
 11. A dressing according to claim 10, whereinthe integrally-formed tube is formed from portions of the first layerand the second layer, by a pair of spaced, sealing lines welding theportions of the first layer and the second layer together, with a spacetherebetween.
 12. In combination, a hyperbaric dressing according toclaim 1 and an absorbent or compression outer bandage or dressing forabsorbing exudate or vacuum means for the removal of exudate.
 13. Adressing according to claim 1, in which the pouch comprises a sheet ofporous material positioned between the fluid-impermeable sheet and thegas-permeable and liquid-impermeable sheet.
 14. A dressing according toclaim 13, wherein the sheet of porous material is adjacent thegas-permeable and liquid impermeable sheet.
 15. A dressing according toclaim 14, wherein the fluid impermeable sheet is applied to the outersurface of the porous sheet remote from the gas-imermeable andliquid-impermeable sheet.
 16. A dressing according to claim 14, whereinan array of apertures is defined in the porous sheet, through whichapertures the first layer and the second layer are sealed together toform the at least one sealed-together in-register portion of the firstand second layers.